使用 + 运算符组合 PHP 中的数组

Question

我最近发现 + 可用于组合 PHP 中的数组。

添加关联数组到关联数组：

$array1 = ["The" => "quick", "brown" => "fox"];
$array2 = ["jumps" => "over", "the" => "lazy dog"];

$combinedArray = $array1 + $array2;

/* Gives:

Array
(
    [The] => quick
    [brown] => fox
    [jumps] => over
    [the] => lazy dog
)

*/

将关联数组添加到索引数组：

$array1 = ["The", "quick", "brown", "fox"];
$array2 = ["jumps" => "over", "the" => "lazy dog"];

$combinedArray = $array1 + $array2;

/* Gives:

Array
(
    [0] => The
    [1] => quick
    [2] => brown
    [3] => fox
    [jumps] => over
    [the] => lazy dog
)

*/

将索引数组添加到关联数组：

$array1 = ["The" => "quick", "brown" => "fox"];
$array2 = ["jumps", "over", "the", "lazy dog"];

$combinedArray = $array1 + $array2;

/* Gives:

Array
(
    [The] => quick
    [brown] => fox
    [0] => jumps
    [1] => over
    [2] => the
    [3] => lazy dog
)

*/

将索引数组添加到索引数组：

$array1 = ["The", "quick", "brown", "fox"];
$array2 = ["jumps", "over", "the", "lazy dog"];

$combinedArray = $array1 + $array2;

/* Gives:

Array
(
    [0] => The
    [1] => quick
    [2] => brown
    [3] => fox
)

*/

其中一个与其他不同。

为什么最后一个不起作用？

Answer 1

发生这种情况是因为上一个示例中的两个数组具有相同的键：

The + operator returns the right-hand array appended to the left-hand array; for keys that exist in both arrays, the elements from the left-hand array will be used, and the matching elements from the right-hand array will be ignored.

Docs

使用 + 运算符组合 PHP 中的数组

Using the + operator to combine arrays in PHP

php

arrays

associative-array